The Stovebolt Site Forums The Shop Area Engine Shop is my coil bad?

i had my truck started and running a few days ago, but then i went to start it the other day and it would turnover good, but there isnt any spark in the points. this has me wondering that the condenser is bad, so i replaced it, but still no spark.

could this mean that my coil is bad? i know every thing is wired right.

thanks for the help.

Coils do go bad. I would try to borrow one before I bought. My experience is that they usually break down when hot. I usually find something else wrong when there is no spark when they are cold. But trying a different coil would probably be your next step, but don't be surprised if it still doesn't work.

bmxinvasion,

If you have a voltage tester make sure you have voltage to the key side of the coil when the key is turned ON. The key side of the coil is marked +. Make sure your key switch is in the ON position, it might not be obvious on this old truck.

If you disconnect the wire that runs from coil to distributor AT the distributor, and with the key ON, alternately touch this wire to ground and remove it. This will fire the coil through the high tension wire when it is held near a ground.

You mentioned in a earlier post you had a polarity reversing switch and that it was disconnected. This switch plays into the ignition system, and especially the points.

If it is disconnected and the truck has started and run fine before then it would be safe to assume this isn't in the equation.

Verifying the presence of voltage with a small tester makes troubleshooting of the type much easier, and they are pretty inexpensive.

Stuart

stuart,
is the positive the wire coming from the key switch under the dash? and the negitive that goes to the distributor? there is no readable marks on my original one.

i got a new coil and i am gonna try it out.
thanks!

Yes..that is how the coil should be wired. + side is from the key switch. - side goes to the distributor.

The VERY most basic test would be to remove the wire from key to coil and scratch it to a place on the engine. With the key ON, it should spark as it is pulled across a ground.

If funds are not a concern, putting a new coil on will take it out of the mix!

Remember, the presence of that polarity reversing switch and the fact that someone removed its wiring required the distributor plate to be grounded. This had to be done by someone after the fact.

You said your engine has started and run fine many times before, right!


Stuart

i got a new coil, got it wired up right....and nothing. it turns over and doesnt fire. the condenser is new, and the points are set to the right gap.

Is the wire from the coil to the distributor somehow grounded out? A lot of times the grommet that runs through the distributor body goes bad and then it grounds out the points.

bmxinvasion,

This is a simple fix! Break the connection at the key to coil wire! With the key ON, that wire needs to spark when touched to ground.

Do that..........if it doesn't spark, no need screwing with anything downstream, the problem is the key switch or wire.

You have to logically dissect this thing...test it, don't replace stuff blindly.

Stuart

thanks for the info stuart, i took the positive wire off from the coil and tested it with a voltage meter. it read 5.5 volts. but when i held it to the clean engine block it didnt spark like you said, unless i am doing it wrong.

thank you. ill try messing with the key switch or something, im hoping you guys will stick with me.

well, it wasnt the coil. it was the key switch. the termanals are rusted and corroded, so im going to see about cleaning it, or replacing it. i hotwired it and it made an attempt to start, but the battery is now dead!!! ugh!! i have to wait till tomorrow now, and its supposed to rain. =[ oh well.

thanks for the help guys!